R. MICHALCZYK RECEIVED 1-MONTH TRAINING IN THE SYNTHESIS OF [6-15N]-DEOXYADENOSINE HYDROGEN PHOSPHONATE AT THE SIR. THE STARTING MATERIAL FOR THE SYNTHESIS, [6-15N]-2'-DEOXYADENOSINE, WAS PROVIDED BY THE SIR. THE SYNTHESIS INVOLVED SEVERAL STEPS. FIRST, [6-15N]-2'-DEOXYADENOSINE WAS N-BENZOYLATED USING BENZOYL CHLORIDE. THE IDENTITY OF FINAL PRODUCT, [6-15N]-N-BENZOYL-2'-DEOXYADENOSINE(N-BZ-DA), WAS CONFIRMED BY TLC & NMR. THE 5'-HYDROXYL GROUP OF N-BZ-DA WAS PROTECTED USING REACTION WITH DIMETHOXYTRITYL CHLORIDE(DMT-C1) WITH THE YIELD OF 77%. THE PRODUCT OF THE REACTION, [6-15N]-N-BENZOYL-5'-DIMETHOXYTRITYL-2'-DEOXYADENOSINE(N-BZ-DMT-DA), WAS PURIFIED USING FLASH CHROMATOGRAPHY ON SILICA GEL COLUMN & WAS DETERMINED TO BE PURE BY TLC & NMR METHODS. THE HYDROGEN PHOSPHONATE GROUP WAS INTRODUCED ON 3'-HYDROXYL OF N-BZ-DMT-DA USING REACTION WITH CHLORODIOXPHOSPHORINONE IN DIOXANE. THE YIELD WAS 96% & THE IDENTITY OF THE PRODUCT WAS CONFIRMED BY 1H, 31P AND 15N NMR. 950MG OF [6-15N]-N- BENZOYL-5'-DIMETHOXYTRITYL-2'-DEOXYADENOSINE WERE OBTAINED AT SIR. THE COMPOUND IS CURRENTLY USED FOR SOLID PHASE SYNTHESIS OF VARIOUS DNA OLIGONUCLEOTIDES IN THE LABORATORY OF DR. I. M. RUSSU. THUS FAR, WE HAVE SYNTHESIZED TWO DNA DEDECAMERS IN WHICH THE ADENINES ARE SPECIFICALLY 6-15N-LABELED: 5'-D(CGCAAATTTGCG)-3', AS A MODEL FOR DNA SEQUENCES CONTAINING AT TRACTS &, 5'-D(CGCGAGCTCGCG)-3', AS A CONTROL. THESE DNA OLIGONUCLEOTIDES WILL BE USED IN NMR EXPERIMENTS TO DETECT AND CHARACTERIZE THREE-CENTER HYDROGEN-BONDS FORMED BY THE N6-AMINO GROUPS. THE PRESENCE OF THE 15N-LABEL AT THESE GROUPS WILL ENABLE US TO OBSERVE DIRECTLY THE NITROGEN ATOMS OF THESE AMINO GROUPS & TO USE 15N EDITING TECHNIQUES FOR THE OBSERVATION OF HYDROGEN ATOMS IN THESE GROUPS, WITH NO INTERFERENCE FROM OTHER PROTON RESONANCES. AT A LATER STAGE, WE WILL SYNTHESIZE 15N-LABELED DNA OLIGONUCLEOTIDES CONTAINING BINDING SITES FOR THE INTEGRATION HF PROTEIN & WE WILL STUDY THEM BY NMR SPECTROSCOPY.